Molded cap and shell casing



Au 19, 1930. A. H. NERO 1,773,690

' MOLDED CAP AND SHELL CASING Fil ed Dec. 17, 1928 2 Sheets-Sheet 1 INVENTOR ARVID H. NERO 3y )zzfa aiZ'orna /s- MMM Aug. 19, 1930.

A. H. NERO MOLDED CAP AND SHELL CASING Filed Deb. 17, 1928 2 Sheets-Sheet 2 j INVENTOR ARVID H.NERO

Patented Aug. 19, 1930 UNITED STATES PATENT OFFICE ARVID H. NERO. OF \VEST HARTFORD, CONNECTICUT, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO THE ARROW-HART & HEGEMAN ELECTRIC COMPANY, OF HARTFORD, CONNECTICUT. A CORPORATION OF CONNECTICUT MOLDED CAP AND SHELL CASING Application filed December 17., 1828. Serial No. 326,545.

The. invention relates to the fastening 01 the sections of a casing for an electric fitting such as the cap and shell sections for a lamp. socket. when such sections are made of molded material.

For someyears it has been the universal practice to form the cap and shell sections for a lamp socket casing from sheet metal and to lite.

provide a lining of sheet insulating material to prevent short circuiting through the housing. The present growing use of gas-filled lamps which create a considerable amount of heat. together with certain other demands of the trade, have made it desirable to make such cap and shell sections of an insulating, material. the preferable substance being a phenolic condensation product such as bake- The most important requirements which must be met by a cap and shell fastening in order that it may be satisfactory for gone all use. are these: (1) The cap must fit on the shell in any one of a. number of relative circumferential positions so that one need not take care to turn the cap to a single engaging position: (2) the full engagement and the separation of the sections must be effected by a short and easily accomplished movement; t3) the fastening must restrainjthe capand shell from relative movement, either endwise or rotative, under the usual conditions of use.

It is theprincipal object of this invention to provide a typc-of fastening which, while meeting these requirements for cap and shell fiist ening's, may be used when'the cap and the shell are made of a molded material. It is an j object also to provide an improved construction of lamp socket casing making practicable the use of a. molded composition material having good insulating properties and an attractive surface finish, e. g. bakelite or other I phenolic condensation product.

A preferred embodiment of the invention is described hereinafter and is illustrated in the accompanying drawing.

In the drawing Figure 1 is a view in elevation, partly in section, of a cap andshell separated but in position to be put together.

Figure 2 is a view, frombeneath, of the cap shown in Figure 1, two of the retaining flanges on the ring being partly broken away.

Figure 3 is a view, in section. looking into the cap from the plane indicated by the line 33-in Figure 1, and taken with the cap and shell in engaged relation and with the ring in position to hold them together.

Figure el is plan view, partly in section, of a cap including a latch.

Figure 5 is a view in elevation, partly in section. of the cap shown in Figure 4.

Fig. 6 is a perspective view of the shell Fig. 7 is a view in section through a retaining ring Fig. 8 is a view in plan.o'f a retaining ring. or a side view of a ring as the ring is placed in Figure 7.

The shell 10 which forms the larger part of the housing is molded from a phenolic condensation product to'a size and shape which will receive the body of an electric lamp socket having a switch incorporated in it. The shoulders ,11 and 19. at appropriate points afford supporting surfaces for the socket body which is inserted from the upper end. Since the casing. made up of the cap and the shell. is of insulating material the usual lining of insulation is not necessary. The slot 13 extending down from the upper rim is made to permit a switch actuator, either a pull chain or a rotary thumb piece, to extend outside of the housing. If a pushthrough switch is used. a similar slot is made on the opposite side. If a keyless socket is u ed of course the slot 13 is unnecessary.

The upper rim of the shell is provided with a number of Uniformly spaced prongs 14 which extend endwise a short distanceabove the main part of the shell. The inner surfaces of the prongs are continuous with the adjacent portions of the inner surface of the shell. The prongs are thicker however than the wall of the shell and thus radially extending lugs 15 are formed. The end corners of the prongs are rounded.

The cap 16 has a bell shape as is usual with this section of a socket casing. The lower rim of the cap has a series of prongs 17 simi lar in shape and equal in number to the prongs 14 on the shell. Each prong has a radial extension beyond the outer wall of the cap to form part of a lug 18. Differing from the lugs on the shell, these lugs 18 on the cap extend above the lower rim of the cap so that, together, their upper or base edges 19 form an interrupted ledge above the rim of the cap for a purpose which will appear hereinafter.

The length of the prongs 14 and 17 on the shell and the ca are approximately equal, those on the cap being slightly the longer so that when caused to interengage, the rim of the shell and the rim of the cap have aslight clearance. This insures that the cap prongs 17 will rest on the portions of the run of the shell between the shell prongs 14. Because of the fact that the base edges of the shell lugs 15 are in the plane of the shell rim and the tips of the cap lugs 18 are flush with the tips of the cap prongs 17, the tip edges of the cap lugs 18 lie in the plane of the base edges of the shell lugs 15. As a result, these registering surfaces or edges form a continuous ledge. To provide easy interengagement of the cap and shell prongs, the prongs are made slightly narrower than the spaces between them, the difference being about 1 or less of arc. 1

TVhen the cap and shell are put together as just described they are restrained from relative rotation by the interengagcment of the prongs on each. To maintain the cap and shell in this position, by restraining them from separation endwise except when sepa- "a ration is desired, a ring 20 of sheet meta provided. This ring encircles the lugs and has a snug fit therewith, suflicientto prevent tree slippage but permitting relative rotation between the casing sections and the ring under manual efl'ort. The ring has an endwise engagement with the cap by means of a portion of the cap which so engages the ring as to hold the cap from endwise movement away from the shell. There are also portions of the shell which are adapted to engage the ring in a selective positions of the latter, so as to be held from endwise movement away from the cap. The portions of the shell so engaged by the ring present surfaces, spe cilically the base edges of the shell lugs 15, faced away from the cap so that their engagement with the ring restrains the cap and shell from endwise movement, the ring being rotatably mounted on the cap and therefore capable of being turned so that its flange portions either engage or lie between these surfaces.

The upper rim of the ring 20 has an inwardly extending flange 21 around its entire circumference. This flange 21 rests on the ledge formed by the upper or base edges 19 of the cap lugs 18. The lower rim of the ring has uniformly spaced inwardly extending flanges or lugs 22 corresponding in num-' her to and of arcuate extent not greater than that of the lugs 18. By reason of the fact that the base edges 19 of the cap lugs are above the rim of the cap, the-ring is=of a width giving good strength and has sufficient bearing surface on the lugs to insure a snug fit.

\Vhen the cap and shell are not connected together,thatis,as shown in Figure 1, the ring is carried by the cap, the upper flange 21 resting on the base edges 19 of the lugs 18 and the lower flanges 22 engaging the tip edges of the same lugs. The ring is put on the cap by slipping it down from the top with the lower flanges 22 in line with the spaces between the lugs 18. It is then turned until the flanges are in engagement with the lower or tip edges of the lugs.

To secure the cap to the shell the two are brought together with the prongs of one between the prongs of the other. Since the prongs are uniformly spaced. it is immaterial in what relative circumferential position the two are engaged. Then, either the ring is held and the cap and shell together are turned, or the latter are held and the ring is turned, in either case sufficiently to bring the lower flanges 22 on the ring into engagement with the base edges of the shell lugs 15. Since the upper flange 2! of the ring still engages the ledge formed by the base edges of the lugs 18. the cap and the shell are held securely together.

The nature of the movement of the ring and of the flanges 22 is seen by a comparison of Figures 2 and 3. In the former, the flanges 22 engage the tip edges of the cap lugs 18 while, in Figure 3, the flanges are in engagement with the base edges of the shell lugs 15. The movement is easily efl'ectcd because the cap and shell lugs form a continuous ledge as described above.

The ring is struck in at a suitable point 23 to provide a detent which bears frictionally against the outer side surface of one of the cap lugs 18 when the cap is ofl'. but which rides ofl' the lug and into the space above a shell lug .15 as the flange 22 adjacent the detent passes out of register with the cap lug. An easily found location for the detent is adjacent that end of the flange 22 which is toward the between-fla nges space with which the detent engaged lug 18' registers when the cap. shell and ring are in fully engaged position. The detent is nearer the upper rim of the ring than the lower, as shown in Figure 1, and thus it lies above the rim of the cap. Hence. it lies above the tip of the shell lugs 15 where the cap and shell are together. It therefore does not engage a shell lug when the ripg is turned but rests in the space above such a ug.

A stop may also be provided by striking in a portion 24 of the upper ring flange 21, to determine the permissive relative movement between the ring and the engaged cap and shell sections and between the ring and the cap when the cap is off. It also limits the movement of the ring to a single direction. Such a stop should be near the end of a between-flangesspace so that it will lie adjacent a cap lug when the cap is off as in Figure 2. Then the cap can be moved on the shell, or the shell in the cap, only until the stop engages the next cap lug. The relative movement thus is limited to the distance between lugs, which is all that is needed.

It is desirable to provide a latch or other means to hold the ring from turning on the sections except when it is to be turned to permit'separation of the cap and the shell. A simple form of latch is shown in Figures 4 and 5. A piece of spring wire 25, bent in they manner shown, ...rests in recesses 26, 27 in adjacent cap lugs 18. The wire 25 has a loop 28 lying in the recess 26 which extends to the tip of the cap lug 18". From this loop, a portion 29 of the wire extends on an are conforming to the periphery of the cap to the recess 27 in the adjacent lug- 18 where it is bent on itself to form the reach 30. The latter has a down-bent end 31 which engages a shoulder 32 on the wall of the recess 26.

The tendency of the reaches 29 and 30 to separate, the reach 30 being held from upward movement by the upper flange 19 of the ring, causes the loop to extend below the tip of the lug l8 when the ring is in such position that the lower flanges 22 are out of engagement with the cap lugs. Any attempt to turn the ring on the sections is resisted by the engagement of the end of a flange 22 with the loop 28. Only when the loop is pressed upwardly so as to lie above the flanges 22, can the rin r be turned to permit the cap and shell to be rcparated.

It will be noted that the loop is not exactly circular but rather U-shaped so that it presents vertical portions for engagement by the ring flan es when it is fully extended as shown in iigure 5. The release of the latch is facilitated by the curved lower end of the loop however since as soon as the loop is pressed upwardly enought so that a flange 22 engages the curved portion, it has a cam effect and forces the loop upwardly. Thus only a very slight manual movement of the loop is required, just as the ring is being turned. to release the latch.

The fastening parts on the cap and shell may be transposed as it is immaterial to the operation on which section the parts are.-= It is not necessary that there bea lug associated with each prong or even that the lugs be radially extended-from the prongs althou h that arrangement, as shown here, is preferable. Many types of latch are possible to prevent turning of the ring on the sections except when desired.

The description above is of the present preferred construction. Variations of it other than those suggested above are possible. I therefore wish to include, within the scope of the protection given me, all such variations from the construction herein described as come within the fair scope of the following claims.

I claim 1. A casing for a lamp socket or the like in which there are cap and shell sections having coacting means torestrain them from relative rotation and in which one section has portions presenting surfaces faced away from the other section, together with a ring in rotatable engagement with said other section and having portions adapted either to lie be tween said surfaces or to engage them to restrain said sections from separation endwise. 2. A casing for a lamp socket or the like in which there are cap and shell sections having coacting means to restrain them from relative rotation and in which one section has portions presenting surfaces faced away from the other section, together with a ring in rotatable engagement with said other section and having portions adapted either to lie between said surfaces or to engage them to restrain said sections from separation endwise and means determining the permissive relative rotation between the ring and the cap and shell sections.

8. A casing for a lamp socket or the like comprising cap and shell sections having interengageable portions to restrain said sections from relative rotation, one section having portions presenting surfaces faced away from the other section, and a ring rotatably mounted with respect to said sections but restrained from movement from said other section toward the one section, said ring having portions adapted either to lie between said surfaces or to engage them to restrain said sections fromseparation endwise.

4. A casing for a lamp socket or the like comprising cap and shell sections, coacting means on said sections for restraining them from relative rotation when put together, laterally extending lugs on said sections and a ring encircling said lugs and free to turn thereon. said ring having a number of flanges adapted to assume either of two positions, one in engagement with, the other lying between III:

the lugs of one of said sections and said ring having also a flange engaging the lugs on the other section in both of said positions.

5. A casing for a lamp socketor the like comprising cap and shell sections, each of which has a number of prongs so arranged that they interengage in any one of'a number of relative circumferential positions to restrain the cap and shell from relative rotation, lugs on one of said sections and a ring which is in endwise engagement with the other section and is rotatable with respect to said sections and which has portions adapted to pass endwise between said lugs and, upon ltm away from the relative rotation between the ring and the cap and shell, to engage; the lugs to restrain said sections from endwise separation.

(i. A casing for a lamp socket or the like comprising cap and shell sections of molded material, each of which has a-. number of prongs so arranged that they inte'rengage in any one of a number of relative circumferential positions to restrain the cap and shell from relative rotation. lugs on one of said sections and a metal ring which is in endwise engagement with the other section and is rotatable with respect to said sections and which has pertions'adapted to pass endwise between said lugs and. upon relative rotation between the ring and the cap and shell, to engage the lugs to restrain said sections from endwise separation.

T. A casing for a lamp socket or the like having cap and shell sections and a ring for uniting said sections. said sections having means capable of interengagement in any one otla number of relative circumferential positions to restrain the cap and shell sections from relative rotation, and one of said sections having a portion adapted to engage said ring so as to be held from endivise movement other section and the other section having portions adapted to engage said ring in selective positions of the ring relative to said sections so as to be held from endwise movement away from the said one section.

8. A casing for a lamp socket or the like having cap and shell sections made of molded material and a metal ring for uniting said sections, said sections having means capable of interengagement in any one of a number of relative circumferential positions to re strain the cap and shell sections from relative rotation. and one of said sections having a. portion adapted to engage said ring so as to be held from endwise movement away from the other section and the other section having portions adapted to engage said ring in selective positions of the ring relative to said sections so as to be held from endwise movement away from the said one section.

9. In combination, cap and shell sections each of which has a number of uniformly spaced endwise extending prongs interengaging with the like prongs of the other. and lugs extending outwardly from certain of said prongs, together wit 1 a ring encircling said lugs and capable of rotation relative to said interengaged sections. said ring having an inwardly extending flange at one rim resting over the base edges of the lugs on one section and having spaced. inwardly extend ing flanges at its other rim adapted to engage either the tip edges of the lugs on said one section or the base edges of the lugs on the other section.

10. A casing for a lamp socket or the like comprising cap and shell sections. a number of similar uniformly spaced, endwise extending prongs on the rim of each of said sections, these prongs being so arranged that the sections may be put together and may be restrained from relative rotation in any of a number ofrelative circumferential positions with the prongs of one section resting on the.

rim of the other section, lugs extending radially outward from said prongs, the lugs on said one section having their tip edges flush with the tips of the prongs on that section and the lugs on the other section having their base edges in the plane of the rim of said other section, and a ring encircling said lugs and capable of rotation thereon, said ring having a flange at one rim engaging the base edges of the lugs on said one section and having flanges on its other rim equal in number to and of arcuate extent not greater than that of the lugs, said flanges being adapted to be turned either into engagement with the tip edges of the lugs on said one section or the base'edges of the lugs on said other section.

ll. A casing for a lamp socket or the like in which there are cap and shell sections having coacting means to restrain them from relative rotation and in which one section has portions presenting surfaces faced away from the other section, together with a ring in rotatable engagement with said other section and having portions adapted either to lie between said surfaces or to engage them to restrain said sections from separation eudwise. and releasable latch means for holding the ring from turning sufficiently on said sections to permit separation thereof.

12. A casing for a lamp socket or the like comprising cap and shell sections having (0-,

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acting means to restrain them from relative rotation, and one section having spaced radially projecting lugs. in combination with a rotatable locking ring in engagement with one section and having spaced radially projecting lugs to engage said lugs on the other section.

In testimony whereof I have signed my name to this specification.

ARVID H. NERO. 

